A light emitting diode (LED) is one of semiconductor devices configured to convert electric energy to light. The light emitting diode has advantages of low power consumption, a semi-permanent lifespan, a quick response speed, safety, and environmental friendliness in comparison with conventional light sources such as a fluorescent light, a light bulb, and the like. Accordingly, many studies for substituting the conventional light sources to light emitting diodes are being carried out.
Recently, use of the light emitting diode as a light source of a lighting apparatus such as various liquid crystal display devices, an electronic display board, a streetlight, or the like that are used indoors and outdoors is increasing. A lighting apparatus using the light emitting diode as the light source includes a light source member including a printed circuit board (PCB) on which the light emitting diode is mounted.
However, since luminance of an area which faces the light emitting diode is generally high in the lighting apparatus, luminance uniformity is difficult to improve.